U.S. patent application number 14/526927 was filed with the patent office on 2015-05-14 for capacitive control interfaces for domestic appliances.
This patent application is currently assigned to WHIRLPOOL CORPORATION. The applicant listed for this patent is WHIRLPOOL CORPORATION. Invention is credited to LEONARDO SERGI.
Application Number | 20150129408 14/526927 |
Document ID | / |
Family ID | 49920440 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150129408 |
Kind Code |
A1 |
SERGI; LEONARDO |
May 14, 2015 |
CAPACITIVE CONTROL INTERFACES FOR DOMESTIC APPLIANCES
Abstract
A capacitive control interface for a domestic appliance includes
an outer layer configured to be pressed by a user, a first
capacitive component, a second capacitive component facing and
separated from the first capacitive component, a first layer of
insulating material between the outer layer and the first
capacitive component, and a second layer of insulating material
beneath the first layer of insulating material and in contact with
the first capacitive component, the second layer having a thru hole
encompassing the second capacitive component, wherein the second
capacitive component faces the first capacitive component at the
thru hole, and wherein the outer layer is flexibly responsive to
pressure and is configured to transfer a flexure to the first
capacitive component.
Inventors: |
SERGI; LEONARDO;
(CASSINETTA, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WHIRLPOOL CORPORATION |
Benton Harbor |
MI |
US |
|
|
Assignee: |
WHIRLPOOL CORPORATION
Benton Harbor
MI
|
Family ID: |
49920440 |
Appl. No.: |
14/526927 |
Filed: |
October 29, 2014 |
Current U.S.
Class: |
200/600 |
Current CPC
Class: |
H03K 2217/960765
20130101; H03K 17/9622 20130101; H03K 17/962 20130101; H03K
2217/960755 20130101; H03K 17/98 20130101; H03K 2017/9613
20130101 |
Class at
Publication: |
200/600 |
International
Class: |
H03K 17/96 20060101
H03K017/96 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2013 |
IT |
MI2013A001877 |
Claims
1. A capacitive control interface for a domestic appliance,
comprising: an outer layer configured to be pressed by a user; a
first capacitive component; a second capacitive component facing
and separated from the first capacitive component; a first layer of
insulating material between the outer layer and the first
capacitive component; and a second layer of insulating material
beneath the first layer of insulating material and in contact with
the first capacitive component, the second layer having a thru hole
encompassing the second capacitive component, wherein the second
capacitive component faces the first capacitive component at the
thru hole, and wherein the outer layer is flexibly responsive to
pressure and is configured to transfer a flexure to the first
capacitive component.
2. An interface as defined in claim 1, further comprising a bottom
layer to which is affixed the second capacitive component, wherein
the first insulating layer is affixed to a bottom face of the outer
layer and to a top face of the first capacitive component, and
wherein the second insulating layer is affixed to a bottom face of
the first capacitive layer and to the bottom layer.
3. An interface as defined in claim 2, wherein the bottom layer
comprises a printed circuit.
4. An interface as defined in claim 3, wherein the printed circuit
is configured to sense a change in at least one of a capacitance or
an inductance due to a flexure of the outer layer being conveyed
through the first insulating layer and first capacitive
component.
5. An interface as defined in claim 1, wherein the first capacitive
component comprises a flat element.
6. An interface as defined in claim 1, wherein the first capacitive
component is formed by depositing a metal layer on a bottom face of
the first layer of insulating material.
7. An interface as defined in claim 1, wherein the first layer of
insulating material and the first capacitive component are
configured to be yielding and flexible at the thru hole of the
second layer of insulating material.
8. An interface as defined in claim 1, further comprising a
plurality of areas of control of the domestic appliance, wherein
the second insulating layer comprises a thru hole for respective
ones of the areas of control.
9. An interface as defined in claim 8, further comprising a
plurality of second capacitive components for respective ones of
the holes, wherein the first capacitive component faces the
plurality of second capacitive components.
10. An interface as defined in claim 1, wherein the outer layer
comprises a metal layer.
11. A method comprising: providing a domestic appliance having a
user interface; electrically isolating a user deflectable metal
surface of the user interface from a first capacitive component of
the user interface; conveying a first flexure of the user
deflectable surface through an electrically insulating layer into a
second flexure of the first capacitive component; and detecting the
first flexure by sensing a change in at least one of a capacitance
or an inductance induced in a second capacitive component as a
distance between the first and second capacitive components changes
in response to the second flexure.
Description
RELATED APPLICATION(S)
[0001] This application claims the priority benefit of Italian
Patent Application No. MI2013A001877, filed on Nov. 12, 2013, the
entirety of which is incorporated herein by reference.
FIELD OF THE DISCLOSURE
[0002] This invention relates generally to domestic appliances and,
more particularly, to capacitive control interfaces for domestic
appliances.
BACKGROUND
[0003] Various types of interfaces are known that are capable of
allowing a user to control an electrical or electronic device or
equipment. With particular reference to the field of domestic
appliances and even more particularly, although not limited to that
of refrigerators, user interfaces are known that have mechanical,
capacitive or capacitive-control pushbuttons.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] A better understanding of the invention will emerge from the
following drawings, attached purely by way of a non-limiting
example, in which:
[0005] FIG. 1 shows a top view of a control interface according to
the invention;
[0006] FIG. 2 shows a section along Line 2-2 in FIG. 1; and
[0007] FIG. 3 shows an enlarged view of the part indicated by A in
FIG. 2.
DETAILED DESCRIPTION
[0008] Mechanical pushbuttons comprise movable parts co-operating
with electrical contacts, whose closing or opening generates a
particular control signal for the domestic appliance or equipment.
These buttons, however, are subject to wear and over time become
not fully reliable.
[0009] Capacitive controls operate on the basis of the variation of
capacitance between two facing conductors, one of which is coupled
with a surface of the interface that the user is touching. These
controls suffer in the event of an accumulation of electrostatic
charges on said surface, however, especially when used in domestic
appliances, such as refrigerators, subject to cleaning operations
of the outer surface performed using woollen or synthetic
cloths.
[0010] Other controls can be piezoelectric or make use of optical
signals (such as infrared signals). However, these controls are
costly and unsuitable for use on domestic appliances, particularly
a refrigerator.
[0011] Interfaces that use inductive controls are also known. For
example, WO2006/064234 describes a detector for measuring the
position between two bodies, a first body comprising an electrical
device and the second at least two inductors energized with an
alternating current, at least one of which is formed by a planar
spiral winding. In this document, the first body causes a change in
inductance of the planar spiral winding and, thus, the ratio of the
inductances of the second body indicates the position of the first
body.
[0012] US 2011/0050626 describes an interface with inductive
control touch keys and comprising illumination elements (light
emitting diodes (LEDs) associated with each touch key which is made
so as to transmit the light, generated by an underlying LED, onto
the outside of the interface.
[0013] EP2028586 describes an inductive detector sensitive to
pressure through a user interface or control interface with a metal
surface. In particular, this patent concerns the fact that a first
inductive component of the detector (formed by a conductor such as
a disc of copper or high magnetic permeability material) is
generally flat and arranged to overlay (at a distance) the second
conductor, also flat, in a confronting relation.
[0014] With particular reference to the metal user interfaces of
capacitive detectors, the known solutions of the state of the art
do not tackle and, therefore, do not resolve the problem relating
to the fact that these detectors can be subject to electrostatic
discharges, particularly if located in particularly dry and windy
environments in which electrostatic charges are present, or due to
rubbing or by contact with electrified bodies.
[0015] In order to avoid the possibility that these discharges
damage the capacitive detector, the above-mentioned interfaces
provided with detectors or capacitive control buttons must be
connected to earth in order to dissipate these discharges. However,
when the user interface is present on a refrigerator door, its
connection to earth becomes very complicated and requires
interventions on the components of the domestic appliance (such as
the door hinges), which are complicated and increase the
refrigerator's production costs.
[0016] The aim of the present invention is to offer a capacitive
user interface or control interface, with a metal outer or contact
surface, which solves the problem of the possible electrostatic
discharges that might damage it, without requiring the device to be
connected to earth.
[0017] In particular, the aim of the invention is to offer a
control interface of the above-mentioned type that is simple to
make, reliable and safe to use for a user and has low production
costs such as not to have a significant impact on the cost of the
domestic appliance.
[0018] These and other aims, which will become clear to a person
skilled in the art, will be achieved by a control interface
according to this disclosure.
[0019] With reference to FIGS. 1 to 3, a control interface or user
interface according to the invention is indicated generally by 1.
It is to be used in particular in a domestic appliance and
specifically in a refrigerator, for example arranged on the outer
surface of a door thereof.
[0020] The interface 1 comprises a body of a layered type, that is,
having various flat components associated with each other. This
body has a first layer 3 having a free metal surface 3A with a
plurality of control areas or "buttons" 4. Note, however, that the
term "button" indicates herein the presence of areas identified by
writing, numbers or something else (in the example, letters of the
alphabet) corresponding to various functions of the domestic
appliance, for example, the selection of the temperature of the
freezer compartment or its adjustment up or down, and does not
require the presence of actual buttons, that is, autonomous bodies
individually movable on the surface 3A.
[0021] The layer 3, at the buttons 4, is yielding, as indicated by
the dashed lines in FIG. 3, when a user presses it (see the hand in
FIGS. 2 and 3 and the arrow P).
[0022] Beneath this layer 3 is a first layer 6 of insulating
material, for example, the material known by the trade name
"Scotch.TM. 7995MP" that is, for example, glued to a bottom face 8
of the above-mentioned layer 3. This layer 6 is yielding too.
[0023] The layer 6 is glued onto a top face 9 of a first capacitive
component 10, which has a flat form and defines an additional layer
of the interface 1. Said first capacitive component 10 is, for
example, a strip of copper or other material that has high magnetic
permeability and is flexible. The first capacitive component 10 can
also be obtained by depositing a layer of metal on a bottom face 30
of the first insulating layer 6.
[0024] On the bottom face 12 of the first capacitive component 10
is fixed, for example glued, a second layer 13 of insulating
material such as, for example, that known by the trade name of
"Scotch.TM. 7957MP", which has a series of thru holes 14 in which
are located second capacitive components 15 (e.g., spiral-shaped
elements) fixed onto a bottom layer 16 of the interface 1 formed by
a printed circuit. The printed circuit 16 is electrically connected
to the second capacitive components 15 and detects their variation
in inductance that occurs, in a known way, as a result of pressing
the outer surface or layer 3. Note that the second capacitive
components 15, located in the holes 14 of the second insulating
layer 13, are present on the bottom layer or printed circuit 16 at
the buttons 4, thus discreetly on said circuit 15.
[0025] When a user presses a control area or button 4 (see FIG. 3),
all the layers 3, 6, 10 and 13 deform under the pressure P. The
first capacitive component 10 bends towards the second 15 inside
the hole 14 and varies its capacitance. This is detected in a known
way by a logic circuit preferably located on the printed circuit 16
and the command corresponding to the button pressed is
performed.
[0026] Thanks to the presence of two insulating layers 6 and 13,
and the particular conformation of layer 13 (holed), the
functionality of the interface 1 remains identical to that of known
interfaces. However, the presence of these layers insulates the
outer surface 3A of the interface from the printed circuit 16 and
from any current that may be induced in the first capacitive
component 10, preventing electrostatic charges from reaching the
outer layer 3 and thus being sensed. The surface 3A can be covered
by a special substrate capable of preventing the presence of
fingerprints or made of another flexible material such as
plastic.
[0027] The invention thus solves the problem of a possible presence
of electrical charges on the metal outer surface of the interface,
while allowing the latter to be embodied with excellent aesthetic
characteristics linked precisely to it being made of metal. All
this with no need to connect this outer surface to earth; a thing
that would be difficult and costly to do in domestic appliances and
in particular in refrigerators.
[0028] Although certain examples have been described herein, the
scope of coverage of this patent is not limited thereto. On the
contrary, this patent covers all methods, apparatus and articles of
manufacture fairly falling within the scope of the claims of this
patent.
* * * * *